Testing's Purpose
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
Testing verifies that software delivers on the project's requirements without unintended errors or side effects — confirmation that the software does what it was expected to do.
Show
A dosage calculator is tested against what the clinic specified, not what the code happens to do.
Watch for
The requirements are the standard; testing the wrong thing proves nothing.